Apparatus for printing



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Patented Oct. 13, 1942 UNITED STATES PATENT OFFCE APPARATUS FOR PRINTING Robert N. S. Whitelaw, Charleston, S. C.

Application April 19, 1940, Serial No. 330,621

8 Claims.

This invention relates to apparatus for printing, particularly by photographic processes, to

prepare copy for photo-offset or photo-lithographie presses.

Separate type characters afford a proper spacing of adjacent letters and characters in the final copy but each font of type for use in a linotype machine or for hand setting is expensive and, in addition to the expense of stocking several fonts of type, considerable time is consumed in changing from one font of type to another when using linotype and similar machines. The usual typewriters are limited to a single font of type and are open to the further objection that the mechanical spacing of all letters and punctuation marks results in an irregular spacing between letters and words. The preparation of copy on typewriters is open to the objection that, whether or not a non-uniform spacing of the letters detracts irom the esthetic effect of the copy, the outlines of the letters and characters are blurred in printing through ribbons by type hammers.

In accordance with this invention, the type letters and symbols are prepared on stencils that may be quickly interchanged on a photographic printing apparatus. Each stencil includes at least one full set of type characters, i. e. letters, numerals and punctuation marks, of a distinctive design, and spacing marks individual to each type character for determining the advance or feed of the record sheet after that character is photographically transferred to the record sheet. The apparatus for impressing or transferring a particular type character from the stencil to the record sheet includes mechanism that is generally similar to a typewriter `in that the character or symbol is selected by depressing a key but, as distinguished from the usual typewriter operation, the advance of the record sheet after the reproduction of a type character is controlled in accordance with the width of that character.

Objects of the invention are to provide improved apparatus ior preparing a printed record or copy from type stencils by a photographic process, the apparatus being characterized by a variable spacing between adjacent letters or symbols in accordance with the width of the reproduced letters and symbols. More specifically, objects of the invention are to provide photographic apparatus in which various fonts or cases of type are prepared on stencils, each stencil including a series of type characters andv spacing marks individual to the several characters for determining the spacing between adjacent characters in the copy. A further object is to provide printing apparatus including a rotatable drum carrying a transparent stencil of the characters to be printed, key-controlled mechanism for selecting the characters to be printed in succession on a record sheet or strip by a photographic process, and a photoelectric system for controlling the spacing of adjacent printed characters.

These and other objects and advantages of the invention will be apparent from the following specification when taken with the accompanying drawings in which:

Fig. 1 is a fragmentary perspective view of an embodiment of the invention;

Fig. 2 is a fragmentary plan view of a character stencil;

Fig. 3 is a schematic view of the optical systems and a diagram of the electrical circuits, and;

Fig. 4 is a fragmentary side elevation of the drum and one of the key-controlled character switches.

In the drawings, the reference numeral i identifies a drum having a circumferential opening or window over which a stencil 2 is detachably mounted, and an open top through which a lamp 3 and two optical systems extend from an upper support, not shown. The first optical system includes lenses and an electrically controlled shutter, within a housing 4, for printing characters of the stencil 2 upon a strip of photographic lm or paper 5, and the second optical system includes lenses and an electrically operated shutter within a housing 6 for passing light to a photocell 1 through marks of the stencil 2 that control the advance of the strip 5 after the printing of a character. The lenses L of the optical systems are shown diagrammatically in Fig. 3 as simple lenses but more elaborate lenses may and preferably will be used in the apparatus.

The drum l is carried by a shaft 8 that telescopes within the hol-low shaft 9 of a motor l0, and is constrained to rotate with shaft 9 by a pin or key Il that extends through longitudinal slots of the shaft 9 and into a circumferential slot in the end of a. lever l2 by which the drum may be adjusted vertically to bring different type rows of the stencil 2 into alinement with the optical system. The outer end of the lever I2 terminates in a conventional key, and a notched bar I3 is positioned adjacent the lever to lock it in each of its adjusted positions. The lever l2 is relatively long and its pivotal mounting permits suicient lateral movement of the outer end of the lever to clear the notched bar when an adjustment is to be made.

The strip of photographic material is drawn from a roll, not shown, and advanced through the guide strips I4 that are opaque except for a. small opening in line with the optical system of the housing 4, and into a storage box I5 by a friction wheel i6 on the feed shaft lll and idler rollers I8 that hold the strip against the feed wheel. For simplicity, the photographic material is shown as a narrow strip for receiving a single line of characters but sheet material may be used when provision is made for line spacing upon the sheet. Shaft il is mounted in an end bearing l@ and an intermediate bearing 2e on a bracket l, and carries a gear 22 that meshes with gear 23 on the motor shaft d. The shaft il is not keyed to the gear 22 but may be coupled to it bya magnetic clutch and brake unit 2d. The detail construction of this unit is not important but it preferably includes two coils 2do, ib, see Fig. 3, that may be selectively energized to couple the shaft to the gear 22 for a drive of the shaft from the motor il?, or alternatively to the fixed support 2l to brake the rotation of the shaft il.

Mechanism for advancing the strip 5 for spacing between words mayI conveniently take the form oi a one-way clutch of the tapered slot and cyhnder type. grammatically in Fig. l, includes a yoke or outer sleeve 25 with tapered slots containing cylinders 2e that are wedged into engagement with a hub 21 on shaft l? by a clockwise movementof the yoke 25. The armature of a coil or solenoid 23.

rocks the yoke clockwise to -advance the feed wheel i5 through a predetermined angle upon each energization or' the coil.

The operation of the apparatus may be most readily understood by nrst considering the'typical stencil sheet of Fig. 2. The stencils are strips of lm that may be either positives or negatives, but, for convenience oi illustration, 'the stencil 2 is shown in Fig. 2 as a positive lm strip, i. e. the type characters and space control marks are V-opadue on a transparent background.

The stencils or hn strips each include a plurality of rows of characters 33 that include the letters of the alphabet, numerals and punctuation marks. It is convenient to place four rows of letters on each stencil that comprise, as shown in Fig. 2, the capital and lower case letters of plain and italic type. The corresponding letters, punctuation marks and numerals are arranged in vertical columns, and each character is accurately located in a particular character space with reference to guide marks, such as holes 3d at the corners of the stencil strip, that serve to locate the strip in a predetermined position upon the drum i. This accuratelocation of the several characters with respect to the guide marks is essential since, as will be explained later, the rotation of the drum to select a particular character for reproduction on the photographic strip e is controlled by an abutment on the drum i. The several characters must therefore be accurately positioned on the stencil, and thereby accurately located with re- .spect to the abutment of the drum, to insure a proper location of a character in printing position upon actuation ofthe key corresponding Yto that character.

-The stencil 2 alsoV carries a series of space controlling marks 35 for each row of charac- The clutch, as shown diaters 33, there being a control mark individual other for Caslon Old Face, 36

Yaacacoo to each character. The control marks are arranged below and are spaced to the left of their respective characters 33 by a distance that results in an advance of the record strip 5, after me printing of a particular character, by a fixed value plus the width of the printed character. The control mark 35A for character A" of the top row, for example, is so spaced from the right edge of the A" character that the control mark 35A is displaced clockwise from the optical axis of the lens system of housing t when the character "A is in printing position in line with the optical axis of the lens system in the housing l. This displacement of the control niark from the optical axis of the lens system determines the feed of the strip 5, under control of the phototube i, as the strip reed shaft il is coupled to the motor shait 9 through the magnetic clutch 2d for an advance ci the strip e, and the clutch and motor circuits are opened when the counterclockwise rotation ci the drum i brings the control mark 35A into line with the lamp and the phototube. Similarly, the several control marks for other ein.: are spaced from the righthand edges of those characters by a constant interval to obtain a controlled advance of the record strip 5 by an amount equal to the width of the printed character plus a nxed increment.

A series of stencils may he prepared by photographing sheets on which characters of dinerent styles or sizes are drawn or printed, for example one stencil for Caslon Old Face, i2 point, anpoint, etc. Stencils may be provided for any desired type face, language or symbols used in printing or for any variation of design in dierent points of a given type face. All stencils are of the same size to be readily interchangeable on the drum i and, as noted above, the character spaces on ali stencils are similarly located for a control of the angular adjustment or the stencil into printing position by an abutment or rib-on the drum i.

As shown in Figs. 1 and 3, the drum i is provided with a vertical rib 3S for closing that one of a bank yof character switches 3l that is selected-by depressing one of the character keys 3B to energize the solenoid 3S of that switch. Each character switch 3'] is mounted on a lever d, Fig. 4, having a lower end that moves over and depresses a spring-pressed button il as it is Yrocked counterclockwise into active-position by its solenoid Se. The rocking of a switch 3l brings it into position for closure by the rib te when the drum i is rotated by the motor de and, as will be explained later, the actuation of a switch 3l results in the opening of the motor circuit at such time that the key-selected character of stencil 2 is in line with the printing optical system of housing A further rotation of the drum t to advance the strip 5 brings the lower enlarged end Se' o f the rib 3c into engagement with the active switch 3l to rock it back into normal inoperative position.

One side of each key controlled switch is connected to a current source, indicated by the leads 32, 33, and the other side is connected to the solenoid 3Q of that key. The other terminal of each solenoid 39 is connected to a bus @d that. is returned to the other side of the current source through the closing coil 15e of a holding switch 35 in the motor circuit. The current lead 221s directly connected to the motor it, and the return connection d6 of the motor extends to contacts of the normally closed switch 41 and normally open switch 46, the other contacts of said switches being connected byleads 43 to the switch 45. Actuation of any character key switch 36 completes a circuit to ener-v gize the solenoid 39 oi.' the corresponding character switch 31 and the closing coil 45e, thus closing switch 45 to complete the motor circuit through the normally closed switch 41. The corresponding contacts of all switches 31 are joined to busses 53, I that are connected, respectively, to the current source lead 42 and, through the opening coil 41o of switch 41 and operating coil 52 of a drum type switch, to the other current source lead 43.

The drum switch, as indicated by the schematic development of a part of its circumference, is given a step-by-step advance by the coil 52 and its pawl 53, and by asecond coil 54 and its pawl 55. The pawls are mounted on the armature of the coils in the usual manner and springs, not shown, restore the armaturesto normal position upon interruption of current flow through the coils. For convenience of illustration, ratchet wheels 56, 51 are shown at opposite ends of the drum switch for cooperation with pawls 53, 55, respectively, but a single ratchet wheel may be used. The pawls 53, 55 each alternately impart a single step movement to the drum when the pawls move upwardly, as viewed in Fig. 3. With the parts in the position shown in Fig. 3, the next step movement of the drum must be made by pawl 53 as current, flow in coil 54 will move pawl 55 over a gap between adjacent teeth of ratchet wheel 51. adjacent teeth of wheel 56 to prevent successive steps of the drum by pawl 53.

Similar gaps are left betweenv The current flow to operating coil 54 of the I drum switch is controlled by the photocell 1 through a vacuum tube amplier 58 that is energized from any appropriate current source, not shown. The amplier is preferably adjustable to permit current iiow to the coil 54 rwhen the cell 1 is illuminated or, alternatively, when the cell is dark. This adjustment, or a corresponding adjustment of the coil 54 and its pawl 55 with respect to the ratchet wheel 51, is necessary when positive and negative lms are to be used interchangeably as the stencils 2.

The drum surface has three rows of cams 60,

6i, 62 for controlling the normally open spring switches 63, 64, 65, respectively, but each have one contact connected to the current lead 43. The other contact of switch 63 is returned to the current lead 42 through the operating coil 66 of a shutter 61 in the housing 4 of the printing optical system. 'I'he second Contact of switch 64 is connected through lead 68 to the closing coil 48e of switch 4B and to the clutch coil 24o of the magnetic clutch and brake unit 2E, and through a branch lead 68 to the operating coil 69 of a shutter 13 in the housing 6 of the second optical system. One terminal of each coil 48o, 24o and 69 is connected directly to current lead 42, and the circuits of the coils are therefore completed when switch 64 is closed. The second contact oi switch 65 is connected by lead 1l tothe brake coil 24h of magnetic brake on the paper feed shaft I1, to the closing coil 41c of switch 41, and to the opening coils 45o and 48o of switches 45 and 48, respectively.

The cam surfaces are so designed that the switches 63, 64 and 65 are open at the completion of a printing cycle, as shown in Fig. 3. A one-step advance of the drum by coil 52 and pawi 53 effects a momentary closure of switch 63 byl cam ring 60, and a closure of switch 64 by cam ring 6l after switch 63 opens. Switch 64 is still closed at the end of the step movement, but opens at thestart of the next step movement by the coil 54 and pawl 55. Switch 65 is closed momentarily by cam surface 62, after switch 64 opens, and opens again before the step is completed.

The operating coil 28 of the space mechanism is connected, in series with a switch 12 that is actuated by the space" bar or key, across the current leads 42, 43, and the lamp 3 is connected directly across the leads.

'I'he method of operation of the described apparatus is as follows. The lever i2 is adjusted to select the row of characters 33 of stencil 2 from which a letter or symbol is to be printed on the strip 5, and the key corresponding to the desired character is depressed to close the associated switch 38. This completes a circuit through the solenoid 33 of the selected character switch '31, and through the closing coil 45o of the holding switch 45 of the motor circuit. Switch 45 is thereby closed to complete the motor circuit, since switch 41 was already closed, and the motor rotates the drum I counterclockwise until the rib 36 of the drum engages and closes the character switch 31 that was rocked into operative position by its solenoid 39. The closure of the switch 31 completed the circuit through the opening coil 41o of switch 41 and through coil 52 of the drum switch. The switch 41 opens to stop the motor I0 with the selected character in line with the optical system within the housing 4. The current flow through coil 52. moved the pawl 53 to advance the drum switch one step to close switches 63 and 64 in succession.

The switch 63 is closed by its cam surface 6U during the first part of the step, thus energizing coil 66 of the shutter 51, and the shutter opens to expose the paper or lm strip 5 to light transmitted through the transparent portion of the stencil 2. "I'he shutter closes automatically, either before or after switch 63 opens, and the switch 64 is then closed by cam surface 6i and remains closed at the end of the step movement of the drum. The switch 64 completes circuits for the clutch coil 24, the closing coil 48 of switch 48, and the operating coil 69 of the shutter 10. The gear 22 is now coupled to the feed shaft I1 by the clutch, the motor circuit is completed through the switch 48 and the holding switch 45, and the shutter 10 is open. The motor rotates the drum i counterclockwise and the feed shaft I1 clockwise until the motor circuit is opened by a change in the illumination at the photocell 1, this change being effected by the movement of the control spot 35 of the printed character into the light path through the shutter 1li and the optical system within the housing 6; The active switch 31 is restored to normal position by abutment 36 during the initial rotation of the drum i, thereby opening the circuit of the coil 52 of pawl 53. Y

The spacing of each control mark 35 from its character is such that, when the character is alined with the printing optical system, the control mark is displaced clockwise from the iight path that will be established when shutter 1|) is opened. When the stencil 2 is a negative nlm strip, as indicated in Fig. 3, the opening of the shutter 10 does not result in an immediate illumination of the cell 1 since an opaque portion of the film is in the light path. The rotation of the drum l continues until the transparent control mark 35 enters the light path, thereby illuminating the photocell I to pass current to the am.- pliiier 58. The resulting amplined current now energizes coil 54 and the pawl E35 is moved to advance the drum switch another step. When a positive iilm is used as the stencil 2, the ampliiier 58 should be adjusted to deliver no current to its output circuit so long as the photocell l is illuminated. Alternatively, the coil c and pawl 55 may be adjusted circumferentlally of the ratchet wheel 5l by one step to' move the pawl 55 into operative engagement with a ratchet tooth upon current ow through coil 51, the effective stroke of pawl 55 then taking placev upon an interruption of current now through the coil The switch 5d is opened by cam ring di during the rst vpart of the step, thus opening the circuits to the clutch coil 2do and to the coil @t of shutter lu, andthe switch t'is closed and then opened by cam 62 during the latter part of the step movement. The shutter l@ is closed by spring mechanism, not shown, upon the interruption of current :dow through coil c5, andthe ldrive of the feed shaft il stops with the opening of the clutch coil circuit. Immediately thereafter, the brake coil 2th is energized by the closing of switch 55 and the motion of feed shaft il is positively arrested. The motor circuit is opened at switches d5 and du since the momentary closing of switch c5 supplies current to the opening coils of those switches and also to the closing coil die of' switch il in the motor circuit It is to be noted that the opening coil d50 of switch d develops su'icient power to overcome the force exerted by the closing coil 35o and that, although switch il is closed, the motor circuit is opened at switch 35 and remains open until another character key is depressed.

The exposed strip 5 is developed inthe usual manner, and may then be cut apart and arranged on a backing sheet to form a master copy for the preparation of a printing plate by a photographic process. The lines may be justified by cutting the strip between the Words and employing variahle spacing between the words in assembling the strip sections on the backing sheet. Clean sharpedged characters are obtained as there is no wear on the stencils, and the general appearance is superior to that obtained by the usual typewriters that are restricted to a constant spacing for all.

Diierent type designs A letters and characters. may be used in preparing copy, particularly for advertising or title pages, as stencils may be readily interchanged on the drum i. The size of the type characters may be varied by selection by diierent stencils or, when a greater variation in size is desired, by separately preparingeach section of the copy that is to be of a given type size by mounting portions oi the developed record strip 5 on a backing sheet, photographing the several sections to prepare prints oi the desired type size, and assembling'the prints to form the master copy.

This application is a continuation-impart or my copending application Ser. No. 279,305, iiled June 15, 1939.

It is to be understood that the invention is not limited to the particular apparatus herein shown and described since the photoelectric control of the spacing may be employed with machines in which the drum is moved mechanically, in response to character keys, to position the stencil for a printing of the selected character.

I claim: l. Apparatus vfor printing characters upon aaoaeee ing' relatively opaque and transparent portions denning a series of characters and a spacing control marls individual to each character, a support for said stencil, a support for a record sheet of photographic material, means manually controlled to produce relative movement of said supports to aline a-selected character with the record sheet and to expose the record sheet to light projectcd through the'selected character, and photoelectric means operative upon completion of the exposure to advance the record sheet by an increment determined by the spacing control mark individual to the selected character.

2. Apparatus as claimed in claim 1, wherein said photoelectric apparatus includes an optical system comprising a light source and a photoelectric cell at opposite sides o the stencil, means operative upon the completion of an exposure to energize the light source and to initiate simultaneously a movement of the stencil with respect to the light source and an advance of the record sheet, and means controlled by the cell when the control mark of the selected character is alined with the light source and cell to interrupt the advance of the record sheet and to de-energize the light source.

3. Apparatus for printing characters upon `photographic material comprising an opaque stencil support having an opening therethrough, a stencil extending over said opening, said stencil having relatively opaque and transparent portions deiining a series of characters, means for supportinga record sheet of the photographic material adjacent said stencil support, a light source and an optical system including a shutter positioned at the side of said stencil support opposite the photographic material, manually controlled means for producing relative movement of said stencil support and the record sheet to position a selected character of the stencil in line with said optical system and the record sheet, means operative upon completion of said relative movement to actuate the shutter to expose the photographic record sheet to light transmitted through the selected character .of the stencil, and photoelectric means for advancing the record sheet with reference to the optical system after the exposure of the record sheet; said photoelectrie means including advance-controlling marks on said stencil and individually located with reference to the respective characters in accordance with the width of the associated character, and normally de-energized means comprising a light source and a photocell for scanning said marks.

4. Apparatus for printing characters upon photographic material, as claimed in claim 3, wherein said photoelectric means includes means operative upon the completion of the exposure to initiate an advance of the record sheet and to energize said scanning means, and means responsive to an alnement of the control mark of the selected character with the scanningmeans, to interrupt the advance of the record sheet and to deencrgize the scanning means.

5. Apparatus for printing characters upon photographic material comprising a drum having a series of characters, means for supporting a photographic material comprising a stencil havrecord sheet of the photographic material adjacent the drum, a light source and optical system including a shutter within said drum, manually controlled means for rotating said drum to position a selected character of the stencil in line with said optical system and the photographic material, means operative upon rotation of said drum for alinement of the selected character with the optical system to actuate said shutter to expose the photographic material to light transmitted through the stencil, and means to advance the record sheet with reference to the optical system after an exposure of the photographic material.

6. Apparatus as claimed in c-laim 5, wherein said stencil has a plurality of rows of type characters, in combination with means for displacing said drum axially to position a desired row of type characters in line with said optical system.

7. Apparatus yas claimed in claim 5, wherein said stencil has a feed control mark individual to each character of said stencil; and said means to advance the photographic material includes a s second optical system within said drum, a photocell, means for initiating a rotation of said drum and an advance of the photographic material upon the completion of an exposure, and means responsive to an alinement of the control mark with the second optical system and said photocell to interrupt the rotation of the drum and the advance of the photographic material.

8. In apparatus for printing characters upon a strip of photographic material, a drum carrying a stencil bearing a series of type characters and a strip feed control mark individual to each type character, means for supporting said strip adjacent said drum, a light source within said drum, a printing ptical system including a shutter Within said drum. a feed control optical system including a shutter within said drum, a photocell exterior to said drum and cooperating with the second optical system, key-controlled means for rotating said drum to position a selected character of said stencil in printing position in line with said printing optical system and said strip, means operative upon arrival of the selected character in printing position to actuate the shutter of the printing optical system., means operative after actuation of the shutter of the printing optical system to open the shutter of the second optical system and to rotate said drum-to move the control mark of the printed character into alinement with the second optical system and said photocell, means to advance said strip during rotation of said drum when the shutter of the second optical system is open, and means energized by movement of the control mark of the printed character into alinement with the second optical system and said photocell to interrupt the rotation of said drum and the advance of said strip.

ROBERT N. S. WHITELAW. 

